Why Install Radiant Heat?
At APEX Thermal Services, we specialize in the design and installation of Radiant Heating Systems. We also specialize in the design and installation of Solar Water Heating Systems and combining Radiant Heating and Solar Water Heating Systems. There are significant energy savings opportunities associated with such a combination, mainly because during much of the heating season, solar hot water systems are capable of producing water temperatures that are useful for radiant heating. Having a conventional fossil-fuel heating system is still recommended, as sizing a solar energy system to provide 100% of your space heating could be cost prohibitive. With radiant heating, a solar hot water system can always be added later, as a retrofit to an existing heating system.
Radiant Heating is the most comfortable and most energy efficient form of space heating. Do you like to be comfortable while the weather is cold outside? Of course you do. Would you enjoy spending 15-20 percent less on heating fuel, while being more comfortable? Probably yes also! Radiant heating makes your work or living space warm and more comfortable down near the floor, where we spend most of our time. In a conventionally heated space, with forced warm air, baseboards or radiators, convection is used to distribute heat throughout the room. These forms of heating promote drafts and cold and warm spots throughout your space. A characteristic of these conventional heating methods is that the warmest air (80 to 90 degrees plus) collects near the ceiling; while down near your toes can still be rather cool (60-65 degrees) and uncomfortable. These conditions leave you tempted to up the thermostat, but then you remember your last fuel bill.
Radiant heating systems do not directly heat the air, they heat objects in your space, including you. The heated objects help heat the air, but at much lower temperatures than conventional heating systems. Thus, the air is less motivated to move toward the ceiling. The heat emitted from radiant heating systems is quite steady and there is little to no perception of the system cycling on and off, unlike baseboards, radiators or forced warm air systems.
Though radiant heated floors are most common, custom installations can include radiant heated walls and ceilings. The same fact holds true, radiant heating heats the objects in a room, not the air. A radiant ceiling will actually heat the floor below it and the objects in your space.
With radiant heated floors, near-ceiling temperatures can actually be about 25 degrees less than that of conventional heating systems, while near-floor temperatures will be about 10-15 degrees warmer, right at your feet. Most folks with radiant heat actually run their thermostats about 3-5 degrees cooler than they did with conventional heating equipment, with improved comfort levels. The improved comfort is undeniable; if you have ever felt it, you know exactly what I am talking about; silent, no drafts, it just comfortably engulfs you. The reduced thermostat settings and lower heating water temperature requirements equate to significant energy savings, typically around 20 percent.
Your radiant heating decisions will likely be somewhat dictated by your situation. New construction situations allow you to design in exactly what you want. Some folks might opt for a radiant slab in the basement and thinner (lighter) slabs on the upper floors. This requires engineering input to deal with the extra weight, shifted door heights and the like. However, the thermal mass of those slabs will provide a very steady heat, compared to other choices.
If youalready occupy the space, a retrofit is your most likely choice, unless you choose a total renovation of the space. Having an unfinished basement would allow for a radiant heating system to be installed from underneath. There are even several choices in this category, staple-up with aluminum plates (best), staple-up without aluminum plates (OK), through floor joists not stapled to bottom of sub-flooring (not preferred; needs higher temperature water to operate, possibly up to 160 degrees). All of these choices require that insulation be installed underneath, so the heat goes up. Fiberglass insulation should be installed with the vapor barrier facing up (bare fiberglass facing down), so you may choose to close in the ceiling after that. We have seen some people install mylar bubble wrap insulation between the floor joists. I deem this acceptable if the open face fiberglass is a concern. We also had a customer go all out, with spray foam, after we installed his staple up radiant system (with aluminum plates). He just had the entire system encapsulated in spray foam. It was a very old and drafty farm house, with visible cracks in the floor boards, clear through into the cold basement. It actually worked out qu ite well. He sprayed his foundation as well, so the basement wasn't cold after that!
Radiant heating can also be installed outdoors, typically referred to as snow-melt systems. They can be very effective at melting snow on driveways, walkways and masonry stairs. They require a pretty heavy boiler or boilers (larger systems), with adequate design focus on ensuring that the boiler(s) never see cold water return temperatures (unless they are condensing boilers). Fuel consumption of these larger boilers could be rather significant, but this would be balanced against the labor costs or plowing contracts, typically associated with clearing the snow. Besides boiler capacity, design decisions are actually very important. Having a sound and logical control strategy and an effective freeze-proof drainage path are critical to a working snow melt system. A poorly designed system can potentially stall, with several inches of slush on the ground, and not have enough power to melt the slush away. In the meantime, a significant amount of energy is being poured into the slush and ultimately lost to the atmosphere. Improved system controls would likely be helpful in this situation, as long as the installed heat source is adequate for the job. A well designed system will make the most of your energy dollars, while keeping your parking lot, driveway and walkways clear, even during a major snowstorm.
Some larger scale municipal snow-melt systems are under consideration for bridges or entire stretches of highway, so this is becoming more and more common.
Can it be powered with solar hot water? Yes, prior to the snow storm, you can pour solar energy into the snow-melt system, ultimately preheating it. You would still need a more conventional heat source for when the snow is falling, unless you have a whole lot of solar heated water stored in some really large tanks. Anything is possible. Ultimately, it is how the pieces are put together and controlled that provides an efficient and effective system. Contact APEX Thermal Services to discuss your radiant heating and snow melt system requirements.